Flame retardants for plastic foams

ABSTRACT

Addition products of polyepoxide resins which have proved to be excellent flame-retardants for plastic foams such as polyurethane foams are disclosed.

United States Patent [191 Bell et al. Aug. 19, 1975 FLAME RETARDANTS FOR PLASTIC [58] Field of Search 260/448.8 A, 398, 403

FOAMS 75 Inventors: Reuben H. Bell, Granville; Kevin M. [56] v Refe'ems c'ted Foley, Hebron, bothof Ohio T D TATES PATENTS [73] Assigneez owens corning Fiberglas 3,113,139 12/1963 Birum et al. 260/448.8 A X C t' T l d Oh" orpora on 0 e o 10 Primary ExaminerPaul F. Shaver [22] Filed: Nov. 23, 1973 Attorney, Agent or Firm-Carl G. Staelin; John W. [21] AppL No: 418 708 Overman; Patrick P. Pacella S l 2 4 6 2 9 [57] ABSTRACT [52] U. C 60/4 8.8 A; 2 0 2.5 A]; 60/3 8;

Addmon products of polyepoxlde resms whlch have 3 3: proved to be excellent flame-retardants for plastic 424/205 6 foams such as polyurethane foams are disclosed. [51 Int. Cl C07l 7/04; C07f 7/18 6 Claims, N0 Drawings FLAME RETARDANTS FOR PLASTIC FOAMS This invention relates to flame retardants for plastic foams.

Plastic foams such as polyurethane foams have found widespread utility in the fields of insulation and structural reinforcement. One factor limiting the commercial utilization of polyurethane foams has been their flammability when exposed to flame or high temperatures. Various additives are known in the art for producing flame resistance in polyurethane foams. For example, the use of elementary sulfur as a flameretardant in some plastic foams is disclosed in US. Pat. No. 3,542,701.

We now have discovered addition products of polyepoxide resins which have proved to be excellent flameretardants for plastic foams such as polyurethane foams. The addition products of this invention are halogenated, and are phosphorus or silane substituted.

Accordingly, an object of this invention is to provide addition products of polyepoxide resins.

Another object of this invention is to provide polyurethane foams incorporating these polyepoxide addition products.

Other object, aspects and advantages of this invention will be apparent to one skilled in the art from the following disclosure and appended claims.

The addition products of this invention are represented by the formula:

wherein R is alkyl, alkoxy, cycloalkyl, cycloalkoxy, aryl, an ester represented by the formula wherein each R" is alkyl, alkoxy, cycloalkyl, cycloalkoxy or aryl, each R having from 1 to 20 carbon atoms, or an ether represented by the formula R -O-R wherein R is as previously defined, or a combination thereof having from 1 to 50 carbon atoms; each R is an alkyl radical having 1 to 20 carbon atoms, each X is chlorine, bromine or fluorine; each Y is phosphorus, the radical I or silane and each m is the integer 2 when Y is phosphorus or the radical PO and the integer 3 when Y is silane. Preferably, each X is chlorine or bromine and each R is an alkyl radical having 1 to 8 carbon atoms.

The polyepoxide resins employed in this invention contain at least 2 epoxide groups in the resin before the addition reactions are carried out. An epoxy resin used most widely is made by condensing epichlorohydrin with bisphenol A. An excess of epichlorohydrin is used to leave epoxy groups on each end of the low molecular weight resin:

CH2CHCH2- Q OCH2CHCH2 O OCH CHCH and CH One method for preparing theaddition products of this invention comprises reacting the polyepoxide resin with a compound represented by the formula:

wherein each X, Y, R and m are as previously defined. The resulting product, which has at least one epoxide group remaining, then is reacted with a halide represented by the formula SiX PX or POX wherein X is as previously defined. This reaction is followed by a reaction with an epoxide represented by the formula wherein R is as previously defined.

As demonstrated by the following examples, the addition products of this invention are excellent flameretardants for plastic foams such as polyurethane foams. This invention is applicable to foams or other cellular or porous structures of synthetic macromolecular substances. The most important foams or structures known at present are those of polystyrene and presence of a suitable catalyst, a blowing agent and generally a surfactant. Both the one-shot technique and the pre-polymer approach can be employed. The amount of polyisocyanate used will vary slightly but in general the total NCO equivalent to total polyol active hydrogen equivalent should be greater than one.

The advantages of this invention are illustrated by the following examples. The reactants, proportions and other specific conditions are presented as being typical and should not be construed to limit the invention unduly.

EXAMPLE I This example demonstrates the preparation of the addition product:

Silicon tetrachloride 1.0 mole )w as placed" in .-a*-1 liter, 3 neck flask equipped with a stir bar, an addition funnel, reflux condenser and thermometer. With stirring, 210 ml of propylene oxide (3.0 moles) then was added to the flask. The flask wascooled in an ice bath during the propylene oxide addition. With stirring and cooling 1.0 mole of was added and followed by the addition of 1.0 moleof phosphorus trichlorides While co'ntiiiuing stirringand cooling, 2.51 moles of propylene oxide was added to the flask. 1 v

The mixture was keptat room temperature overnight and excess propylene oxide wasremoved under vacuum. The preparation was employed as a fire retardant in Example lll.

' IIEXAMPLE 11 This example demonstrates the preparation of the adi dition product:

The process of Example I was repeated except that 1.0 mole of was employed instead of 1.0 mole of CHCH2 The preparation was employed as a fire retardant in Example IV.

' EXAMPLE In A polyurethane sample incorporating the addition product of Example I was prepared with the following ingredients.

NCO/OH index 1.1

The sample was prepared by the one-shot method comprising adding the surfactant and flame retardant material to the polyol. The blowing agent then was added followed by the water and catalyst. The run was completed by adding the isocyanate, mixing and dispensing the mixture and allowing the foam to rise into a continuous bun.

EXAMPLE IV The process of Example III was repeated except that the addition product of Example II was employed in stead of the addition product of Example 1.

EXAMPLE V The process of Example II] was repeated except that no additive flame retardant material was employed, i.e., the addition products of Examples 1 and Il.

EXAMPLE Vl Samples of the polyurethane foams prepared in Examples III to V were tested for flammability according to the following procedure. A sample of each foam was mounted in a vertical chimney with a wire glass front and ignited with a Bunsen burner for seconds. The duration of the flame after removal of the burner and the percent by weight retained by each foam sample were recorded.

Percent Weight Average Extinguish Retention Time, seconds Example III 82.5 0 Example IV 78.4 0.6 Example V (control) 73.0 0.8

A comparison of these properties reveals that the addition products of this invention are effective flame retardants for plastic foams such as polyurethane foams,

i.e., less foam is consumed with shorter extinguishing wherein R is a divalent group selected from the group consisting of alkyl, alkoxy, cycloalkyl, cycloalkoxy, aryl, an ester represented by the formula wherein each R is a divalent group selected from the group consisting of alkyl, alkoxy, cycloalkyl oraryl, each R having 1 to 20 carbon atoms,'or an ether represented by the formula R 0 R is as defined above, or a combination thereof having from 1 to 50 carbon atoms; each R is an alkyl radical having 1 to 20 carbon atoms, each X is chlorine, bromine or fluorine; one Y is phosphorus or the radical and the other Y is silicon and each m is the integer 2 when Y is phosphorus or the radical PO and the integer 3 when Y is silicon.

- 2. An addition product represented by the formula:

wherein R is a divalent group selected from the group consisting of alkyl, alkoxy, cycloalkyl, cycloalkoxy, aryl, an ester represented by the formula wherein each R is a divalent group selected from the group consisting of alkyl, alkoxy, cycloalkyl or aryl, each R having 1 to 20 carbon atoms, or an ether represented by the formula R O R is as defined above, or a combination thereof having from 1 to 50 carbon atoms; each R is an alkyl radical having 1 to 20 carbon atoms, each X is chlorine, bromine or fluorine; and one Y is phosphorus and the other Y is silicon and each m is the integer 2 when Y is phosphorus and the integer 3 when y is silicon.

3. An addition product according to claim 2 wherein each X is chlorine or bromine and each R is an alkyl radical having I to 8 carbon atoms.

4. An addition product according to claim 2 wherein the addition product is prepared from a polyepoxide having at least 2 epoxide groups in the polyepoxide before an addition reaction is carried out.

5. An addition product according to claim 2 represented by the formula:

6. An addition product according to claim 2 reprel5 sented by the formula: 

1. AN ADDITION PRODUCT REPRESENTED BY THE FORLULA:
 2. An addition product represented by the formula:
 3. An addition product according to claim 2 wherein each X is chlorine or bromine and each R2 is an alkyl radical having 1 to 8 carbon atoms.
 4. An addition product according to claim 2 wherein the addition product is prepared from a polyepoxide having at least 2 epoxide groups in the polyepoxide before an addition reaction is carried out.
 5. An addition product according to claim 2 represented by the formula:
 6. An addition product according to claim 2 represented by the formula: 